Abstract
Factors known to trigger the emergence or re-emergence of infectious diseases include globalisation, population growth, migration, international trade, urbanisation, forest destruction, climate change, loss of biodiversity, poverty, famine and war. Epidemics not only lead to disastrous loss of human life but may also have catastrophic economic, political and social consequences. Outbreaks may rapidly jeopardize industry, trade or tourism in countries that are unprepared. Dengue is currently spreading throughout the tropics, while another arbovirus, chikungunya, infected 30 to 75 % of the population in some parts of the Indian Ocean region between 2005 and 2006. Chikungunya is now spreading through India, where more than a million people have so far been infected. This viral disease can cause lasting disability, and the first deaths were recently reported in La Réunion and Mayotte. All countries are at risk from emerging or re-emerging diseases, but the consequences are far worse in poor countries. Microbial pathogens and wild mammals, birds and arthropods do not respect man-made borders. There is still time to act against this threat of emerging and re-emerging infectious diseases, through prevention, anticipation, monitoring and research.